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United States Patent |
5,079,390
|
Costanzo
,   et al.
|
January 7, 1992
|
Lock-out device for circuit breakers
Abstract
Disclosed is a device that can be placed on the lever arm of a switch and
locked to prevent the switch from being turned on. The device comprises a
rigid body having a clasping device for removably fixing the rigid body to
the lever arm, an aperture through the rigid body in which the shackle of
a lock can be placed, positioned so that when the shackle is in the
aperture access to the clasping device is blocked, and a bracing portion
which contacts the switch to prevent its lever arm from being rotated when
the device is attached thereto.
Inventors:
|
Costanzo; John J. (Niagara Falls, NY);
Marsden; Donald H. (Niagara Falls, NY);
Yoder; Michael R. (N. Tonawanda, NY)
|
Assignee:
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Occidental Chemical Corporation (Niagara Falls, NY)
|
Appl. No.:
|
679848 |
Filed:
|
April 3, 1991 |
Current U.S. Class: |
200/43.14; 200/50.25 |
Intern'l Class: |
H01H 027/10 |
Field of Search: |
200/50 R,50 AA,50 A,50 C,41.14
|
References Cited
U.S. Patent Documents
3296391 | Jan., 1967 | Zavertnik et al. | 200/43.
|
3657672 | Apr., 1972 | Flick et al.
| |
4978816 | Dec., 1990 | Castongvay et al. | 200/43.
|
Foreign Patent Documents |
677653 | Sep., 1961 | CA | 200/43.
|
172771 | Feb., 1986 | EP.
| |
202991 | Nov., 1986 | EP.
| |
245127A | Nov., 1987 | EP | 200/43.
|
2730634 | Jan., 1979 | DE | 200/43.
|
Primary Examiner: Picard; Leo P.
Assistant Examiner: Donovan; Lincoln
Attorney, Agent or Firm: Tao; James F., Fuerle; Richard D.
Claims
We claim:
1. A device for preventing a rotatable lever arm of a switch from being
rotated, comprising a rigid body having
(a) clasping means for removably attaching said rigid body to said lever
arm;
(b) an aperture through said rigid body in which the shackle of a lock can
be placed, positioned so that when said shackle is in said aperture access
to said clasping means is blocked; and
(c) a bracing portion which can contact said switch to prevent said lever
arm from being rotated when said device is attached to said lever arm.
2. A device according to claim 1 wherein said rigid body is made of steel.
3. A device according to claim 1 wherein said rigid body is made of
plastic.
4. A device according to claim 1 wherein said clasping means is a set
screw.
5. A device according to claim 1 wherein said aperture is a hole.
6. A device according to claim 1 wherein said aperture is a slot.
7. A device for preventing the lever arm of a switch from being flipped,
comprising
(a) a rigid body having a first aperture for receiving said lever arm and a
bracing portion which contacts said switch to prevent said lever arm from
being flipped when said lever arm is secured in said first aperture;
(b) clasping means for removably attaching said rigid body to said lever
arm;
(c) a second aperture in said rigid body through which said clasping means
can be engaged; and
(d) a third aperture in said rigid body through which the shackle of a lock
can pass, said third aperture crossing said second aperture, whereby
access to said clasping means is blocked when said shackle is in said
third aperture.
8. A device according to claim 7 wherein said rigid body is made of steel.
9. A device according to claim 7 wherein said rigid body is made of
plastic.
10. A device according to claim 7 wherein said clasping means is a set
screw.
11. A device according to claim 7 wherein said first aperture is a hole.
12. A device according to claim 7 wherein said first aperture is a slot.
13. A lock-out device for a circuit breaker that has a lever arm extending
at an acute angle from an exposed surface comprising
(a) a rigid rectangular body having a first aperture therein at an angle
approximating said acute angle, for receiving said lever arm when said
body rests on said exposed surface;
(b) clasping means for attaching said body to said lever arm;
(c) an access port in said body through which said clasping means can be
engaged; and
(d) a second aperture in said rigid body crossing said access port, through
which the shackle of a lock can pass blocking access to said clasping
means.
14. A device according to claim 13 wherein said rigid body is made of
steel.
15. A device according to claim 13 wherein said rigid body is made of
plastic.
16. A device according to claim 13 wherein said clasping means is a set
screw.
17. A device according to claim 13 wherein said first aperture is a hole.
18. A device according to claim 13 wherein said first aperture is a slot.
Description
BACKGROUND OF THE INVENTION
This invention relates to a device that can be placed on a switch and
locked to prevent the switch from being turned on. In particular, it
relates to a device that has means for clasping the lever arm of a switch,
where the clasping means are rendered inaccessible when the shackle of a
lock is passed through the device.
In January of 1990 the Occupational Safety and Health Administration (OSHA)
Lock-Out Rule (29 CFR 1910.147) went into effect. This rule requires that
all energy sources be locked out before any work is done on an electrical
circuit. The purpose of the rule is to prevent someone from turning on a
circuit while work is being performed on that circuit.
At the present time circuits can be locked out by locking the entire
circuit box. However, this is not satisfactory because circuit breakers
that control circuits that are not being worked on are inaccessible and
can not be reset. Various devices are available for locking out individual
circuit breakers but these devices are not entirely satisfactory because
they lack the strength to resist tampering, they can be applied to only
the breakers of a specific manufacturer, they cannot be locked with a
multiple lock out, or they cannot be applied so that several circuit
breakers can be locked out at the same time.
SUMMARY OF THE INVENTION
We have invented a lock-out device for circuit breakers and other switches.
Our device is simple but effective in preventing someone from turning a
switch on or off. The device is so secure, in fact, that when properly
applied, it can usually not be forced off without breaking the lever arm
of the switch. The device can be applied to switches made by almost any
manufacturer and is designed so that a number of independent switches can
be locked out at the same time. The simple design of the device makes it
relatively inexpensive to manufacture.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view partially in section illustrating a certain
presently preferred embodiment of a lock-out device according to this
invention as it is applied to a circuit breaker.
FIG. 2 is an isometric drawing in section of an alternative embodiment of a
certain presently preferred lock-out device according to this invention.
DESCRIPTION OF THE INVENTION
In FIG. 1, lock-out device 1 consists of a rigid body 2 made from a single
piece of steel and having an aperture therethrough 3 of a size appropriate
for receiving lever arm 4 of circuit breaker 5. The angle, .phi., of
aperture 3 is approximately the same angle that lever arm 4 of circuit
breaker 5 makes with exposed surface 6 of circuit breaker 5. Angle .phi.
is typically an acute angle, usually about 70.degree.. Rigid body 2 of
lock-out device 1 is also provided with a set screw 7 which is preferably
directed at the base of lever arm 4 on the side opposite angle .phi..
Access to set screw 7 is achieved through aperture 8 in rigid body 2.
Rigid body 2 is further provided with another aperature 9 into which can
be placed shackle 10 of lock 11. Lock-out device 1 is provided with
bracing portion 12 which rests against exposed surface 6 of circuit
breaker 5 to prevent lever arm 4 from being rotated when locking device 1
is attached to lever arm 4.
To apply lock-out device 1 to circuit breaker 5, it is placed over lever
arm 4 as shown in FIG. 1 and set screw 7 is tightened to secure lock-out
device 1 to lever arm 4. Shackle 10 of lock 11 is then passed through
aperture 9, effectively blocking access to set screw 7 and thereby
preventing anyone from removing lock-out device 1.
In FIG. 2, lock-out device 13 consists of a rigid body 14, which can be
made of a plastic material, such as a molded phenolaldehyde resin (e.g.,
phenolformaldehyde). Rigid body 14 is provided with a hole 15 for
receiving the lever arm of a switch. Molded into rigid body 14 is a metal
insert 16 into which is threaded metal set screw 17. Access to set screw
17 is obtained by means of hole 18 and such access can be blocked by
placing a shackle through another hole 19, which crosses hole 18. Bracing
portion 20 rests against the exposed portion of the switch.
Variations on the devices shown in the drawings are also contemplated
within the scope of this invention. For example, other means for attaching
the locking device to the lever arm can be used such as, for example, a
clamp. The lock-out device of this invention is applicable to any type of
switch having a lever arm which rotates, such as a circuit breaker or a
light switch.
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